Low temperature plasma assisted atomic layer deposition in nitrogen carrier gas studied by optical emission spectroscopy

A low temperature plasma assisted atomic layer deposition process from tetrakis (dimethylamino)-titanium (TDMAT) and oxygen plasma was investigated using optical emission spectroscopy in a commercial TFS-500 atomic layer deposition reactor in industrial-like conditions with different plasma powers to optimize the plasma-assisted deposition process and to develop a tool for process control. The major emitting species recognized were the nitrogen first followed by the second positive system, carbon monoxide, nitrogen monoxide (γ)-system, atomic carbon and atomic nitrogen. The process measurements were compared to background measurements to see the process induced differences. CHx appearance in the plasma lowered the intensities of CO, NO and N2 1st+ system peaks. Also, the nitrogen atom content varied in the process measurements. By monitoring the affected species and vibrational temperature, the effect of TDMAT oxidation on the surface could be seen through the resulting changes in the plasma emission.